The LX1664/64A and LX1665/65A are monolithic switching regulator controller IC's designed to provide a low cost, high performance adjustable power supply for advanced microprocessors and other applications requiring a very fast transient response and a high degree of accuracy. Short-circuit Current Limiting without Expensive Current Sense Resistors. Current-sensing mechanism can use PCB trace resistance or the parasitic resistance of the main inductor. The LX1664A a nd LX1665A have reduced current sense comparator threshold for optimum performance using a sense resistor. For applications requiring a high degree of accuracy, a conventional sense resistor can be used to sense current.